Abstract: Objective To evaluate the difference between acetabular component template and femoral component template,and analyze the possible causes of the measurement differences. Methods From March 2018 to March 2019,125 patients admitted to our center who underwent total hip arthroplasty were selected.The difference between the prosthesis size measured by the computer template measurement software and the actual size used in the operation was retrospectively analyzed. Results The digital templating predicted the size of the prosthetic implant accurately with difference less than 4mm for the acetabular components,and less than 3mm for the femoral components.In terms of degree of difference,planning by acetabular component template was significantly more inaccurate than femoral component template (error within 4 mm,7.2% vs 0.8%,P<0.05).In addition,planning was more accurate in patients with femoral head necrosis than in patients with hip dysplasia (error within 4 mm,2 cases vs 7 cases,P<0.05). Conclusion The application of template measurement software to assist the selection of prosthesis has a high accuracy and validity within a certain error range.The measurement accuracy of the acetabular prosthesis is slightly lower than that of the femoral prosthesis.Specific anatomic abnomalies may be responsible for the difference in measurements.